Log home construction is significantly eased by providing logs of constant diameter along the log length. Logs of all species include a taper from a maximum diameter at the trunk or butt ends to a minimum diameter at the crown or top ends. Those building log homes from tapered logs must take care to alternate the tapers. Notches at corners must also be varied to accommodate different diameters of the intersecting logs. This significantly extends the amount of labor and time required to complete the construction. To further exacerbate the problem, the degree of taper may vary substantially from one log to the next. Each log in a construction project must therefor be carefully selected not only for length and diameter, but also for the degree of taper.
Various log turning machines have been developed in the past to solve the various problems presented by tapered logs. One form of turning machine is basically a very large lathe. The log is driven to rotate and a cutter is moved along to cut the log length to a desired diameter. This requires an extremely large machine, especially for long logs. Feeding and discharge of successive logs to such machines also becomes a time consuming and difficult problem. A finished log must be disengaged and removed from the machine, and a new log must be positioned and engaged by the machine before the next turning operation can take place.
An innovative solution to the problems presented by conventional lathe machines involves passing successive logs lengthwise through a rotary cutter head. The time consuming steps of feeding, discharging and set-up of the machine may be nearly eliminated by feeding successive logs in end-to-end relation through the rotary cutter head. The logs are cut to a constant diameter as they are fed through the machine.
Rotary cutter head machines were a marked advancement in reducing the overall costs and equipment required for turning logs, but such machines were not without difficulties. Firstly, a log moving through a rotary cutter head must be well supported along its length during the cutting operation or the finished log may not be straight. This is accomplished by the infeed conveying mechanism upstream of the cutter head.
Since the infeed conveyor cannot pass through the cutter head (due to the rotating cutters), a separate support mechanism must be provided downstream of the cutter head. This support mechanism must be accurately positioned to guide the cut part of the log along through the finish of the cut. Lateral shifting of the cut part of the log downstream of the cutter head will result in the cutter head gouging the log, or an unacceptable crook or bend may be cut into that part of the log which is presently moving through the cutter head.
The present inventor has experimented in the past with different forms of guides that have operated with only minimal success in preventing logs from shifting as they pass through a rotating cutter head. It was not until advent of the present guide arrangement and cutter head that high numbers of logs could be turned accurately and straight.
It is therefor a first objective of the present invention to provide a log guide and cutting arrangement that will reliably form logs with a circular cross sectional shape along a straight central axis.
A still further objective is to provide such an arrangement that is adjustable to form logs of different finished log diameters.
The above and still further objectives and advantages may become apparent from the drawings and description provided below and in which the best mode presently known is disclosed for carrying out the present invention.